NXP GreenChip flyback
controllers TEA173x
Bring high efficiency and low standby
power to low-cost applications
Optimized for applications requiring up to 75 W, these cost-effective devices deliver 90%
efficiency, use <100 mW of power, and enable slim, compact designs.
Key features (TEA1733, TEA1738)
`` SMPS controller IC enabling low-cost applications
`` Large input voltage range (12 to 30 V)
`` Very low supply current during start-up and restart `
(10 μA typ)
`` Low supply current during normal operation `
(0.5 mA typ without load)
`` Overpower or high/low line compensation
`` Adjustable overpower time-out & restart timer
`` Reduced EMI
`` High efficiency at low output power levels
`` Slope compensation for CCM operation
`` Low and adjustable OverCurrent Protection (OCP) trip level
`` Adjustable soft start operation
`` Two protection inputs (e.g. for input UVP and OVP, OTP and
output OVP)
`` Over-temperature protection
`` Low-cost, industry-standard packages
Applications
`` Adapters for notebooks, netbooks, printers
`` LCD monitors
`` DCM and CCM power supplies
Additional features (TEA1738)
`` Higher efficiency at medium and low loads
`` Higher frequency at overpower
`` VCC over-voltage protection
`` Pin-for-pin compatible with TEA1733 in SO8 package
All the TEA1733 and TEA1738 variants are produced in NXP’s
ABCD silicon-on-insulator (SoI) technology. As a result, the
devices offer high-speed protection, are insensitive to `
latch-up, and are less dependent on temperature.
NXP’s GreenChip TEA1733 and TEA1738 devices combine
fixed-frequency operation at high output power with
frequency reduction at low output power. The result is high
efficiency over the total load range. Frequency jitter reduces
electromagnetic interference (EMI), and both ICs are equipped
with several protections to enhance robustness and reliability.
The standard versions of the TEA1733 and TEA1738 operate
at 67 kHz and cause safe restart for over-power time-outs. The
TEA1733L and TEA1738L versions trigger latched protection
for over-power time-outs. The TEA1733 is also available in
derivatives that operate at 90 kHz: the TEA1733A includes safe
restart, the TEA1733M offers latched protection.
Signal interference is also lower, and a wider VCC range is
possible.
For both devices, during startup, the supply voltage VCC is
charged by the current through a start-up resistor. Since the
current consumption of the IC is roughly 10 µA (typ) at startup,
there’s no need for high-voltage circuitry.
Low current consumption and frequency reduction means
that a standby power of less than 100 mW is possible. With
the right external resistors and X-cap, the measured standby
power can be as low as 48 mW at 115 Vac and 84 mW at `
230 Vac for a typical 65 W, 19.5 V power supply.
Both devices offer a number of protection features, including
input and output over/under-voltage protection, over-power
protection, and internal/external over-temperature protection.
The devices are adjustable for over-power time-out, and the
support high/low line compensation.
TEA1733(L) vs. TEA1738(L)
Designed as a drop-in replacement for the TEA1733(L), the
TEA1738(L) uses the same low-cost, industry-standard SO8
package and has the same pinning, but delivers even higher
efficiency.
TEA1733 block diagram
The TEA1738(L) uses a lower frequency at medium loads to
obtain higher efficiency at medium and low loads. It uses a
higher frequency during overpower conditions to obtain a
temporary increase in output power. The frequency reduction
slope (Vco mode) has been changed to prevent audible noise
and achieve the lowest possible standby power. The VINSENSE
high-protection function has been removed, to reduce reset
time after an overvoltage condition. The maximum duty cycle
has been increased, to support larger dips in mains voltage.
Over-voltage protection has been added to the VCC line, to
improve the accuracy of internal protection.
In the L version, which offers latched protection, there are
new techniques for preventing false OPP triggering and for
preventing latched protection reset due to premature VCC
UVLO. Note that replacing the TEA1733(L) with the TEA1738(L)
may impact EMI and protection behavior. An application check
is recommended before finalizing any replacements.
Adapter demo board
The NXP demo board UM10385 gives an example of a 65 W
notebook adapter. The TEA1733 helps the system achieve an
EnergySTAR average efficiency of roughly 90% at `
115 and 230 Vac. The board also features extremely low power
consumption at no load (115 V = <60 mW at no load, `
230 V = <100 mW at no load).
TEA1738 application diagram
TEA173x versions
Parameter
TEA1733
TEA1733L
TEA1738
TEA1738L
Safe restart protection
Yes
TEA1733M
Yes
Latched protection
Yes
SO8 package
Yes
Yes
Yes
Yes
Yes
90 kHz
90 kHz
Yes
(TEA1733L only)
DIP8 package
Operating frequency
TEA1733A
67 kHz
67 kHz
TEA173x protection parameters
Parameter Protection
TEA1733
TEA1733L
TEA1733A
TEA1733M
TEA1738
TEA1738L
Cycle by Cycle
Cycle by Cycle
Cycle by Cycle
Cycle by Cycle
Cycle by Cycle
Cycle by Cycle
OVP`
(Over Voltage Protection, supply pin Vcc)
external
external
external
external
integrated
integrated
pin PROTECT, level > Vhigh (PROTECT)
(typ. 0.8 V)
Latched
Latched
Latched
Latched
Latched
Latched
pin PROTECT, level < Vlow (PROTECT) `
(typ. 0.5 V)
Latched
Latched
Latched
Latched
Latched
Latched
pin OPTIMER, VOPTIMER (prot) `
voltage > 2.5 V (typ.)
Safe
Restart
Latched
Safe
Restart
Latched
Safe
Restart
Latched
IC Over Temperature Protection (OTP)
Latched
Latched
Latched
Latched
Latched
Latched
pin VINSENSE, level < Vlow (VINSENSE)
(typ. 0.69 V)
Safe
Restart
Safe
Restart
Safe
Restart
Safe
Restart
Safe
Restart
Safe
Restart
pin VINSENSE, level > Vhigh (VINSENSE)
(typ.3.5 V)
Safe
Restart
Safe
Restart
Safe
Restart
Safe
Restart
Not
Implemented
Not
Implemented
OCP`
(Over Current Protection, primary side)
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© 2011 NXP Semiconductors N.V.
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Date of release: February 2011
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